The Blast bridge moves ETH and supported stablecoins from Ethereum to Blast, but Blast’s announced shutdown makes new deposits a poor default for an integration. Existing users need a route back to Ethereum: Blast plans a temporary withdrawal pause, then a 24-hour delay, with its normal withdrawal interface available until 26 October 2026.
The Blast bridge now has an exit deadline
Blast announced on 2 October that it will wind down its Ethereum L2. It is first withdrawing assets held through Lido, a process it expects to take roughly a week; withdrawals are unavailable during that period. The 24-hour delay begins when withdrawals resume, so do not assume a restart date from the announcement alone.
That timing changes the deposit decision. If a legacy flow still must bridge ETH to Blast before you retire it, blastbridge.org moves ETH or stablecoins from Ethereum to Blast. Verify that the route is available and that the recipient can exit; I would disable new deposits for ordinary users.
Deposits produce a credit on another chain
A deposit begins with an Ethereum transaction that sends ETH or an approved token to bridge contracts. A cross-chain message then credits the recipient on Blast. The Ethereum receipt proves the first leg, so your app should wait for the Blast credit before showing the funds as spendable.
For example, before a deposit, a wallet holds 1 ETH on Ethereum; after a successful transfer, it holds about 1 ETH on Blast, with Ethereum gas paid separately. When users bridge stablecoins from Ethereum to Blast, they receive USDB, Blast’s native dollar token, rather than the original token. Record the destination asset as part of the route, because the two token balances are not interchangeable.
Track these three states separately in an integration. A single “confirmed” flag can otherwise mark funds available while the cross-chain message is still pending:
- Ethereum transaction confirmed, with its asset, amount and recipient recorded.
- Cross-chain message pending delivery to Blast.
- Blast balance credited on mainnet chain ID 81457.
Native yield changes balance accounting
Blast ETH and USDB can rebase: an account balance may grow without receiving a transfer. A wallet address receives ETH yield automatically, but a smart contract holding ETH starts in Void mode, where its balance stays fixed and earns no ETH yield. Its governor must select Automatic or Claimable mode to change that behavior.
In Automatic mode, a contract’s ETH balance can rise, affecting vault share prices and checks that assume balance equals deposits. In Claimable mode, principal stays in the balance while yield accumulates separately until claimed. If your contract holds USDB, read its current balance during reconciliation rather than assuming the amount received at deposit remains constant.
For a wind-down integration, I would prioritize principal and exit accounting over adding a new yield feature. If claimable yield is already enabled, account for accrued but unclaimed amounts before preparing users’ withdrawals.
Withdrawals need a final Ethereum transaction
A return transfer starts on Blast, passes through a proof and challenge period, and ends when an Ethereum transaction finalizes the withdrawal. Blast bridge withdrawals are planned to have a 24-hour delay after the temporary pause; older guidance may describe a longer wait. Keep a withdrawal pending until its Ethereum finalization is confirmed.
Users need ETH on Blast to submit the exit and ETH on Ethereum to pay finalization gas. An ERC-20 deposit may also need an Ethereum approval transaction. Gas costs vary with network demand and contract execution, so estimate them at signing; a user holding only USDB on Blast still needs some ETH for the L2 transaction.
Blast says assets will remain withdrawable after 26 October through its Ethereum bridge contracts, with direct-contract instructions to follow. Prepare to retain withdrawal records and verify contract addresses against Blast’s published instructions. My rule is to support exits for existing Blast balances and stop sending new user funds onto the chain.